Follow the link for more information. Sword Art Online light novel volume 1 cover. Japanese light novel series written by Reki Kawahara and illustrated by abec. Sword Art Online has received widespread commercial success, with the light novels having over 20 million copies sold worldwide. The anime series has received mixed to positive reviews, with praise for its animation, musical score and exploration of the psychological aspects of virtual reality, but criticisms for its pacing and writing. The light novel series spans several virtual reality worlds, beginning with the titular world of Sword Art Online. Kayaba appears and tells the players that they must beat all 100 floors of Aincrad, a steel castle which is the setting of SAO, if they wish to be free.